Biochemical and clinical studies on human pancreatic deoxyribonuclease I inhibitor

Human pancreatic Deoxyribonuclease I (DNase I), inhibitor was partially purified from duodenal juice of healthy subjects collected in the Pancreozymin-Secretin test, by a procedure which included ammonium sulfate fractionation, DEAE cellulose fractionation, Sepharose 4B affinity chromatography, and gel filtration. The final preparation inhibited DNase I only, and had no inhibitory activity on pancreatic RNase, and trypsin. The inhibitor had a molecular weight of approximately 40,000, as determined by gel filtration, and showed the same mobility as skeletal muscle actin on SDS gel electrophoresis. Then clinical studies were made on the DNase I inhibitor in duodenal juice obtained after administration of Pancreozymin and Secretin to patients with various pancreatic diseases. In patients with suspected chronic pancreatitis with whom the ordinary test, containing the assay of the total volume, amylase output and maximum bicarbonate concentration of duodenal juice had produced normal results, the DNase I inhibitor output was observed to be higher than that in control subjects. While it was lower in patients with confirmed chronic pancreatitis than in control subjects. There results imply that DNase I inhibitor output may be an indicator of the pancreatic inflammation state and be useful for the early detection of pancreatic diseases.